--- title: "Usage" --- Prerequisites: - Set up and add envars to [Infisical Cloud](https://app.infisical.com) or your self-hosted instance. - Obtain an API Key in your user settings to be included in requests to the Infisical API. Using Infisical's API to manage secrets requires a basic understanding of the system and its underlying cryptography detailed [here](/security/overview). ## Concepts - Each user has a public/private key pair that is stored with the platform; private keys are encrypted locally by the user's password before being sent off to the server during the account signup process. - Each (encrypted) secret belongs to a project and environment. - Each project has an (encrypted) project key used to encrypt the secrets within that project; Infisical stores copies of the project key, for each member of that project, encrypted under each member's public key. - Secrets are encrypted symmetrically by your copy of the project key belonging to the project containing. - Infisical uses AES256-GCM and [TweetNaCl.js](https://tweetnacl.js.org/#/) for symmetric and asymmetric encryption/decryption operations.